KEVAN CHRISTIE

SCIENTISTS have made a breakthrough in understanding Parkinson’s disease after finding that people living with the illness often have a mutated form of a gene, which may not repair damaged cells.

They believe this explains why those with the disease have damaged and dysfunctional nerve cells which, instead of being destroyed or repaired, start to accumulate in the body.

Researchers at Trinity College Dublin analysed the effect of the Parkin gene and discovered that in response to specific types of cell damage, it can trigger the self-destruction of damaged nerve cells by switching on a controlled process of “cellular suicide”.

The Trinity research group, led by Smurfit Professor of Medical Genetics, Professor Seamus Martin, has just published its findings in Cell Reports journal.

Although mutation of Parkin has been known to lead to an early-onset form of Parkinson’s for many years, understanding what it actually did within cells has been a difficult mystery to solve.

Prof Martin and colleagues have discovered that in response to specific types of cell damage, Parkin can trigger the self-destruction of “injured” nerve cells by switching on a controlled process of cellular suicide called apoptosis.

The Martin laboratory, funded by Science Foundation Ireland, found that damage to mitochondria (which function as cellular battery packs) activates the Parkin protein, which results in one of two different outcomes – ­either self-destruction or a repair mode. Which outcome was chosen depended on the degree of damage suffered by the cellular battery packs.

Importantly, these new findings suggest that one of the problems in Parkinson’s disease may be the failure to clear away sick nerve cells with faulty cellular battery packs, to make way for healthy replacements.

Prof Martin stated: “This discovery is surprising and turns on its head the way we thought that Parkin functions. Until now, we have thought of Parkin as a brake on cell death within nerve cells, helping to delay their death.

“However, our new data suggests the contrary: Parkin may in fact help to weed out injured and sick nerve cells, which probably facilitates their replacement. This suggests that Parkinson’s disease could result from the accumulation of defective neurons due to the failure of this cellular weeding process.”